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DIY solution for HDMI to 8ch digital out 1 year 5 months ago #55688

  • mga2009
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Sadly I don't have a scope (it's on my top list of purchases this year).

By noise, I mean digital noise or timing issues; I am no expert but I've had similar "noise" or issues when connecting 2x ADAU1701 over TDM which later was solved by putting one in "slave mode". I would definetly say no noise floor related, and this regard, it might be as clean as I can expect from this kind of setup, and much better that the noise floor when using the ADAU1701 integrated ADC. 

 

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DIY solution for HDMI to 8ch digital out 1 year 2 months ago #57230

  • superchuko
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Nice find! I've been searching for a way to get 8 channel audio from HDMI to a proper audio interface, and I thought I'd have to give up. There seems to be a version of this that's a bit cheaper as well, www.aliexpress.com/item/33026273034.html , just lacking the HDMI output (which I don't really need since I have a splitter). This should work going into my USB Streamer, to my audio interface with ADAT, correct?

Also; any idea if it accepts HDMI 2.0?

Edit: I guess the USB Streamer doesn't have an I2S input when in ADAT mode, according to the documentation.

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DIY solution for HDMI to 8ch digital out 1 year 2 months ago #57239

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I'm kind of annoyed that I can't find anything to connect this with an audio interface, other than using the USB Streamer for I2S to USB, and having that outputted via another USB Streamer, or something.

There's the AK4101A which can apparently convert I2S to AES/EBU, and the Coolaudio V1401 which might be able to do I2S to ADAT, (though certain posts disagree on whether it supports I2S). But I'm not an engineer, and I can't seem to find anything off the shelf that supports converting I2S to ADAT or AES/EBU.

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DIY solution for HDMI to 8ch digital out 1 year 1 month ago #57512

  • rhollan
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Hmm. I used the Blackmagic 4xAES deembedder and didn't notice any objectionable noise, though I didn't have the equipment to measure it. I followed with a Symetrix Lucid 8824 DAC and Crown amps, so not the best quality, but fairly good for my first theater effort.

I have since found that Monoprice has an HDMI  to 3G SDI converter that is "HDCP compliant". I have verified that it will take a HDCP 1.4 1080p signal and pass it on to SDI, and thence to another Monoprice 3G SDI to HDMI converter.

Rather than go the nanoAVR-HD/nanoAVR-DL route, I sprung for a DDRC-88D to do bass management and Dirac Live all in one box. I've also ordered an AJA 3G-AM AES deembedder/embedder. Finally, I picked up an Oppo-205 intended for use primarily as a DAC, and an Emotiva XSP-1 analog preamp/subwoofer crossover with HT Bypass.

The idea is this: Separate (non-Oppo 205) HDMI sources will feed an HD Fury Diva, acting as a 4k HDMI switch, 1080p "audio HDMI' downsampler, and eARC audio extractor from the TV. The audio HDMI will go into the HDMI to 3G SDI converter, through the AJA 3G-AM deembedder/embedder, and in to the 3G SDI to HDMI converter to feed the HDMI in of the Oppo 205. An Okto DAC8 might be marginally better, but they're so backlogged, they are no longer taking orders. In any case, it is very hard to beat the analog output stage of the Oppo 205.

The AJA-3M will both feed 8 channels of AES audio to the DDRC-88D, and take 8 channels of AES audio from the DDRC-88D and re-embed them into the SDI stream, which is then converted to HDMI to feed the Oppop 205.

The Oppo can certainly play disks itself, and it's dedicated balanced stereo output feeds the audio side of the XSP-1 preamp, while it's left, sub, right unbalanced outputs feed the theater side. The XSP-1 will do analog bass crossover between left and right audio sources to a pair of stereo left and right speakers and stereo subs. When switched to HT bypass, it will take the theater inputs and simply distribute the subwoofer input between each of the two subs (close to their respective speakers and equidistant from the main listening position so not needing delay adjustment between them). The idea is to use the Oppo for pure stereo listening and the other HDMI source for theater. The Oppo itself will do distance correction for the other speakers, but no bass management, leaving this to the DDRC-88D. If one wanted, one could use these other sources to run stereo through Dirac if desired, with DDRC-88D bass management and use the XSP-1 theater path with mono subs, or through the 88D WITHOUT stereo bass management, and the XSP-1 WITH analog bass management. Essentially, except for "pure" listening, the Oppo 205 serves as little more than an 8 channel DAC (albeit a very good one).

With this upgrade, I also sprang for two Apollon Audio Purifi amps: a 3 channel for LCR, and a 4 channel for rear and side surrounds, and picked up four BG Radia 420 surround speakers to match the rest of my setup (I moved and left the PD6-LCRi surrounds in the wall for the new homeowner).

Theoretical specs are thus:

Oppo 205 balanced stereo SINAD:       0.00013  118dB
Oppo 205 unbalanced 8ch SINAD:       0.00018  115dB

XSP-1 balanced to balanced SINAD:     0.0004   108 dB
XSP-1 unbalanced to balanced SINAD: 0.0003   110 dB

Apollon amp SINAD:                             0.00013  118 dB

Overall stereo SINAD:                           0.00066  104 dB
Overall theater SINAD:                         0.00061  104 dB

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DIY solution for HDMI to 8ch digital out 1 year 1 month ago #57536

  • rhollan
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This is my new processing shelf.

An HD Fury Diva accepts 4k HDMI and routes it to a TV from up to four sources. It also processes ARC and eARC from said TV. The 7.1ch LPCM audio over 1080p HDMI is routed to a Monoprice HDMI to 3G SDI converter (which strips HDCP, an AJA 3G-AM AES/EBU audio deembedder/embedded which sends processed audio to a Monoprice 3G SDI to HDMI converter and loops through the SDI to my old Blackmagic SDI to audio converter.

The AJA 3G-AM interfaces to the minidsp DDRC-88D for bass management and Dirac Live processing before going back out as 3G SDI.

The SDI to Audio converter serves only to drive a Symmetrix Lucid 8824 AD/DA converter used now solely as an 7 channel amplitude display.

The processed audio over HDMI will feed the Oppo 205 HDMI input and the Oppo will serve as DAC feeding the 3 channel and 4 channel Apollon amps via an Emotiva XSP-1 for left and right and subs for stereo sub crossover duty.

SINAD of the whole system should be above 100 dB to the speakers. 
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Last edit: by rhollan. Reason: Typo
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